OFFSET
4,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 4..1000
MAPLE
seq( `if`(n<7, n-3, add(floor((n-3)/floor((n-6)/j)), j=1..n-6)), n=4..60); # G. C. Greubel, Dec 10 2019
MATHEMATICA
Table[If[n<7, n-3, Sum[Floor[(n-3)/Floor[(n-6)/j]], {j, n-6}]], {n, 4, 60}] (* G. C. Greubel, Dec 10 2019 *)
PROG
(PARI) a(n) = if(n<7, n-3, sum(j=1, n-6, (n-3)\((n-6)\j)) );
vector(60, n, a(n+3) ) \\ G. C. Greubel, Dec 10 2019
(Magma) [n lt 7 select n-3 else (&+[Floor((n-3)/Floor((n-6)/j)): j in [1..n-6]]): n in [4..60]]; // G. C. Greubel, Dec 10 2019
(Sage)
def a(n):
if (n<7): return n-3
else: return sum(floor((n-3)/floor((n-6)/j)) for j in (1..n-6))
[a(n) for n in (4..60)] # G. C. Greubel, Dec 10 2019
(GAP)
a:= function(n)
if n<7 then return n-3;
else return Sum([1..n-6], j-> Int((n-3)/Int((n-6)/j)) );
fi; end;
List([4..60], n-> a(n) ); # G. C. Greubel, Dec 10 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved